U.S. patent application number 12/847743 was filed with the patent office on 2011-02-03 for medical device surface electrode.
This patent application is currently assigned to Medtronic, Inc.. Invention is credited to David B. Engmark, John Eric Lovins, Andrew J. Ries, Scott J. Robinson, Randy S. Roles, David J. Saltzman, Eric John Wengreen.
Application Number | 20110029027 12/847743 |
Document ID | / |
Family ID | 43527734 |
Filed Date | 2011-02-03 |
United States Patent
Application |
20110029027 |
Kind Code |
A1 |
Wengreen; Eric John ; et
al. |
February 3, 2011 |
MEDICAL DEVICE SURFACE ELECTRODE
Abstract
Structures and methods relating to electrodes for incorporation
into a feedthrough with a profile adapted for subcutaneous sensing
of physiologic and cardiac signals. Electrode assemblies are
adapted for integration with feedthroughs and provide reliable
insulation from the implantable medical device housing. Various
structures and manufacturing processes are implemented to provide a
large sensing surface with a low profile. The subcutaneous sensing
electrode assembly can provide a leadless sensing system and
further enhances installation and follow-up procedures.
Inventors: |
Wengreen; Eric John;
(Stanford, CA) ; Ries; Andrew J.; (Lino Lakes,
MN) ; Saltzman; David J.; (Minneapolis, MN) ;
Roles; Randy S.; (Elk River, MN) ; Robinson; Scott
J.; (Forest Lake, MN) ; Engmark; David B.;
(Bethel, MN) ; Lovins; John Eric; (Oakdale,
MN) |
Correspondence
Address: |
MEDTRONIC, INC.
710 MEDTRONIC PARKWAY NE
MINNEAPOLIS
MN
55432-9924
US
|
Assignee: |
Medtronic, Inc.
Minneapolis
MN
|
Family ID: |
43527734 |
Appl. No.: |
12/847743 |
Filed: |
July 30, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61230537 |
Jul 31, 2009 |
|
|
|
Current U.S.
Class: |
607/2 |
Current CPC
Class: |
A61N 1/3754 20130101;
A61N 1/3756 20130101 |
Class at
Publication: |
607/2 |
International
Class: |
A61N 1/375 20060101
A61N001/375 |
Claims
1. An implantable medical device comprising: a housing having an
inner surface and an outer surface; an electrode assembly coupled
to the housing, the electrode assembly comprising: an insulator
coupled to the outer surface of the housing; an electrode coupled
to the insulator; a feedthrough passes through the housing, the
feedthrough includes an electrically conductive pin coupled to the
electrode; an insulator cup coupled to the electrode; and a
retention bracket coupled to the insulator cup and to the
housing.
2. The electrode assembly of claim 1, wherein the retention bracket
is welded to the housing.
3. The electrode assembly of claim 1, wherein the retention bracket
is molded into the insulator cup.
4. The electrode assembly of claim 1, wherein the insulator cup
snaps onto the retention bracket.
5. The electrode assembly of claim 1, wherein the insulator cup
protrudes less than about 0.175 inches perpendicular from the
housing outer wall.
6. The electrode assembly of claim 1, wherein the insulator cup
protrudes less than about 0.1 inches perpendicular from the housing
outer wall.
7. The electrode assembly of claim 1, wherein adhesive fills a void
between the insulator cup and the outer housing wall.
8. The electrode assembly of claim 1, wherein the electrode is
non-planar.
9. The electrode assembly of claim 1, wherein the electrode is dome
shaped.
10. The electrode assembly of claim 1, wherein the electrode is
rectangular.
11. The electrode assembly of claim 1, wherein the electrode has a
high-surface area coating.
12. The electrode assembly of claim 1, wherein the insulator cup is
captured between the electrode and the housing.
13. The electrode assembly of claim 1, wherein the plane that
contains the perimeter of the outer electrode surface is
approximately aligned with the plane that contains the perimeter of
the housing area that is covered by the insulator cup.
14. The electrode assembly of claim 1, wherein the assembly
includes at least one adhesive fill hole or vent.
15. An implantable medical device (IMD) having a hermetically
sealed housing having a housing outer wall exposed to the body and
a housing inner wall enclosing sensing circuitry within said
housing for processing electrical signals of the body detected
between at least two sense electrodes, comprising: at least one
sense electrode comprises an electrical feedthrough mounted to
extend between said housing first side and said housing second
side, said feedthrough comprising a ferrule having an inner ferrule
surface extending between a ferrule first end and a ferrule second
end, an electrically conductive feedthrough pin extending between a
feedthrough pin first end and a feedthrough pin second end, and an
electrical insulator extending between said feedthrough pin and
said ferrule inner wall and supporting said feedthrough pin; means
for mounting said ferrule wall first end to extend said feedthrough
pin through said housing to expose said feedthrough pin first end
to the body and to hermetically enclose said feedthrough pin second
end within said housing; and means for electrically coupling said
feedthrough pin second end with said sensing circuitry thereby
enabling said feedthrough pin first end is connected to a first
sense electrode operable in conjunction with a second sense
electrode coupled with the sensing circuitry to enable sensing of
electrical signals of the body; further comprising a preformed
insulator to insulate the first sense electrode from the ferrule
first end and the housing outer wall, wherein the insulator cup is
coupled to a retention bracket that is secured to the housing.
16. The electrode assembly of claim 15, wherein the retention
bracket is welded to the housing.
17. The electrode assembly of claim 16, wherein the retention
bracket is molded into the insulator cup.
18. The electrode assembly of claim 17, wherein the insulator cup
snaps onto the retention bracket.
19. The electrode assembly of claim 16, wherein the insulator cup
protrudes less than about 0.175 inches perpendicular from the
housing outer wall.
20. The electrode assembly of claim 16, wherein the insulator cup
protrudes less than about 0.1 inches perpendicular from the housing
outer wall.
21. The electrode assembly of claim 16, wherein adhesive fills the
void between the insulator cup and the outer housing wall.
22. The electrode assembly of claim 16, wherein the electrode is
non-planar.
23. The electrode assembly of claim 16, wherein the electrode is
dome shaped.
24. The electrode assembly of claim 16, wherein the electrode is
rectangular.
25. The electrode assembly of claim 16, wherein the electrode has a
high-surface area coating.
26. The electrode assembly of claim 16, wherein the insulator cup
is captured between the electrode and the housing.
27. The electrode assembly of claim 16, wherein the plane that
contains the perimeter of the outer electrode surface is
approximately aligned with the plane that contains the perimeter of
the housing area that is covered by the insulator cup.
28. The electrode assembly of claim 16, wherein the assembly
includes at least one adhesive fill hole or vent.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/230,537, filed on Jul. 31, 2009. The disclosure
of the above application is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to implantable
medical devices; and, more particularly, to securing electrodes to
implantable medical devices.
BACKGROUND
[0003] Since the implantation of the first cardiac pacemaker,
implantable IMD technology has advanced with the development of
sophisticated implantable pulse generators (IPGs), implantable
cardioverter-defibrillators (ICDs) arrhythmia control devices
designed to detect arrhythmias and deliver appropriate therapies.
Detection and discrimination between various arrhythmic episodes in
order to trigger the delivery of an appropriate therapy is of
considerable interest. Prescription for implantation and
programming of the implanted device are based on the analysis of
the PQRST electrocardiogram (ECG) and the electro gram (EGM).
Waveforms are typically separated for such analysis into the P-wave
and R-wave in systems that are designed to detect the
depolarization of the atrium and ventricle respectively. Such
systems employ detection of the occurrence of the P-wave and
R-wave, analysis of the rate, regularity, and onset of variations
in the rate of recurrence of the P-wave and R-wave, the morphology
of the P-wave and R-wave and the direction of propagation of the
depolarization represented by the P-wave and R-wave in the heart.
Detection, analysis and storage of such EGM data within implanted
medical devices are well known in the art. Acquisition and use of
ECG tracing(s), on the other hand, has generally been limited to
the use of an external ECG recording machine attached to the
patient via surface electrodes of one sort or another.
[0004] ECG systems that detect and analyze the PQRST complex depend
upon the spatial orientation and number of externally applied
electrodes available near or around the heart to detect or sense
the cardiac depolarization wave front. Implantable medical device
systems increasingly can include communication means between
implanted devices and/or an external device, for example, a
programming console, monitoring system, and similar systems. For
diagnostic purposes, it is desirable that the implanted device
communicate information regarding the device's operational status
and the patient's condition to the physician or clinician.
Implantable devices can transmit or telemeter a digitized
electrical signal to display electrical cardiac activity (e.g., an
ECG, EGM, or the like) for storage, display and/or analysis by an
external device.
[0005] To diagnose and measure cardiac events, a cardiologist has
several tools from which to choose. Such tools include twelve-lead
electrocardiograms, exercise stress electrocardiograms, Holter
monitoring, radioisotope imaging, coronary angiography, myocardial
biopsy, and blood serum enzyme tests. In spite of these advances in
the medical device art, the surface ECG has remained a standard
diagnostic tool. A twelve-lead ECG is typically the first procedure
used to determine cardiac status prior to implanting a pacing
system. An ECG recording device is attached to the patient through
ECG leads connected to skin electrodes arrayed on the patient's
body so as to achieve a recording that displays the cardiac
waveforms in any one of twelve possible vectors. An example of ECG
leads with skin electrodes may be seen with respect to U.S. Pat.
No. 6,622,046 to Fraley et al. issued Sep. 16, 2003, and assigned
to the assignee of the present invention. Fraley et al. discloses a
feed through used in combination with an electrode to sense the
human body's electrical activity. It is desirable to develop new
mechanical features related to securing surface ECG electrodes to
the housing of an implantable medical device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The following drawings are illustrative of particular
embodiments of the present disclosure and therefore do not limit
the scope of the disclosure. The drawings are not to scale (unless
so stated) and are intended for use in conjunction with the
explanations in the following detailed description. Embodiments of
the present disclosure will hereinafter be described in conjunction
with the appended drawings, wherein like numerals denote like
elements.
[0007] FIG. 1 is an illustration of a body-implantable device
system in accordance with the present disclosure, including a
hermetically sealed device implanted in a patient and an external
programming unit;
[0008] FIG. 2 is a perspective view of an exemplary external
programming unit of FIG. 1;
[0009] FIG. 3 is a schematic view of an implantable medical
device;
[0010] FIG. 4 is a schematic view of an exemplary electrode
connected to a retention cup;
[0011] FIG. 5 is a schematic view of an electrode connected to a
retention cup of FIG. 4 cutaway along lines 5-5;
[0012] FIG. 6A is a side view of electrode connected to a retention
cup;
[0013] FIG. 6B is an angled top view of electrode connected to a
retention cup;
[0014] FIG. 7 is a schematic view of an implantable medical device
with a dome-shaped electrode;
[0015] FIG. 8 depicts a schematic view of an implantable device
with a rectangular hermetic housing;
[0016] FIG. 9 depicts a low profile electrode assembly of the
implantable medical device shown in FIG. 8;
[0017] FIG. 10A is a schematic view of a narrow hermetic housing
with a feed through connected thereto;
[0018] FIG. 10B is a schematic view of a retention bracket
connected to the housing;
[0019] FIG. 10C depicts an insulator cup connected to the retention
bracket of FIG. 10B;
[0020] FIG. 10D depicts an electrode placed in the insulator cup of
FIG. 10C;
[0021] FIG. 10E depicts a conductive wire that is flush with the
surface of the electrode of FIG. 10D;
[0022] FIG. 11 depicts a top exterior view of a retention bracket
connected to an electrode and housing;
[0023] FIG. 12 depicts a cross-sectional view of a retention
bracket connected to an electrode and housing;
[0024] FIG. 13 depicts an enlarged view of the retention bracket
connected to an electrode and housing of FIG. 12; and
[0025] FIG. 14 depicts a schematic view of a retention bracket for
supporting a surface electrode.
DETAILED DESCRIPTION
[0026] The following description of the preferred embodiments is
merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses. For purposes of clarity,
similar reference numbers are used in the drawings to identify
similar elements. The devices described herein include an exemplary
number of leads, etc. One will understand that the components,
including number and kind, may be varied without altering the scope
of the disclosure. Also, devices according to various embodiments
may be used in any appropriate diagnostic or treatment procedure,
including a cardiac procedure.
[0027] FIG. 1 depicts an implantable medical device system adapted
for use in accordance with the present disclosure. The medical
device system shown in FIG. 1 includes an implantable medical
device (IMD) 10 that has been implanted in patient 12. Although the
present disclosure will be described herein in an embodiment which
includes a pacemaker, the disclosure may be practiced in connection
with numerous other types of implantable medical device systems
including neurostimulators, implantable defibrillators, and
insertable cardiac monitors.
[0028] In accordance with conventional practice in the art, IMD 10
is housed within a hermetically sealed, biologically inert outer
housing or casing, which may comprise a metal such as titanium,
stainless steel, glass, epoxy, or other suitable material. In other
embodiments, the IMD housing is not hermetically sealed. One or
more leads, collectively identified with reference numeral 14 in
FIG. 1 are electrically coupled to IMD 10 in a conventional manner
and extend into the patient's heart 16 via a vein 18. The leads 14
are joined to the IMD 10 by plugging the leads into the connector
module 11. Disposed generally near the distal end of leads 14 are
one or more exposed conductive electrodes for receiving electrical
cardiac signals and/or for delivering electrical pacing stimuli to
heart 16. Leads 14 may be implanted with their distal end(s)
situated in the atrium and/or ventricle of heart 16.
[0029] Also depicted in FIG. 1 is an external programming unit 20
for non-invasive communication with IMD 10 via uplink and downlink
communication channels, to be hereinafter described in further
detail. Associated with programming unit 20 is a programming head
22, in accordance with conventional medical device programming
systems, for facilitating two-way communication between IMD 10 and
programmer 20. In many known implantable device systems, a
programming head such as that depicted in FIG. 1 is positioned on
the patient's body over the implant site of the device, typically
within 2- to 3-inches of skin contact, such that one or more
antennae within the head can send RF signals to, and receive RF
signals from, an antenna disposed within the hermetic enclosure of
the implanted device or disposed within the connector block of the
device, in accordance with common practice in the art.
[0030] FIG. 2 is a perspective view of an exemplary programming
unit 20. Internally, programmer 20 includes a processing unit (not
shown) that in accordance with the present disclosure is a personal
computer type motherboard, e.g., a computer motherboard including
an Intel Pentium 3, Intel.RTM. Core.TM. microprocessor or other
suitable processors and related circuitry such as digital
memory.
[0031] Programmer 20 comprises an outer shell 60, which is
preferably made of thermal plastic or another suitably rugged yet
relatively lightweight material. A carrying handle, designated
generally as 62 in FIG. 2, is integrally formed into the front of
outer shell 60. With handle 62, programmer 20 can be carried like a
briefcase.
[0032] An articulating display screen 64 is disposed on the upper
surface of outer shell 60. Display screen 64 folds down into a
closed position (not shown) when programmer 20 is not in use,
thereby reducing the size of programmer 20 and protecting the
display surface of display 64 during transportation and storage
thereof.
[0033] A disk drive is disposed within outer shell 60 and is
accessible via a disk insertion slot (not shown). A hard disk drive
is also disposed within outer shell 60, and it is contemplated that
a hard disk drive activity indicator, (e.g., an LED, not shown)
could be provided to give a visible indication of hard disk
activation. In the perspective view of FIG. 2, programmer 20 is
shown with articulating display screen 64.
[0034] An input device 26 such as a mouse is connected to
programmer 20 which serves as an on-screen pointer in a graphical
user interface presented via display screen 64. Input device 26
allows a user to input data.
[0035] To sense signals from tissue of, for example, the heart
and/or deliver electrical stimuli to tissue, a low profile surface
electrode assembly 110 can be connected to housing 100 of a variety
of differently shaped IMDs such as IMD 10, tubular or pill-shaped
IMD 150 and rectangular-shaped IMD 190 depicted in FIGS. 3 and 7-9,
respectively.
[0036] Electrode assembly 110 includes an electrode with a
feedthrough 150 such that feedthrough 150 secures a electrode 120
to the external surface of the housing 100 of IMD 10. An example of
ECG leads with skin electrodes 120 may be seen with respect to U.S.
Pat. No. 6,622,046 to Fraley et al. issued Sep. 16, 2003, and
assigned to the assignee of the present invention; the disclosure
of which is incorporated by reference in its entirety herein. In
other embodiments (such as in FIGS. 10-14) the feedthrough does not
secure the electrode to the housing. In one or more embodiments,
the electrode 120 can be coated with a high surface area coating to
increase the surface area of the electrode 120 without increasing
the length and width of the electrode 120. For example, an
electrode 120 can be coated with iridium oxide to increase the
surface area.
[0037] Feedthrough 150 can be inserted or placed through the
housing 100. An example of a feedthrough 150 passing through an
electrode may be seen with respect to U.S. Pat. No. 6,622,046 to
Fraley et al. issued Sep. 16, 2003, and assigned to the assignee of
the present invention, the disclosure of which is incorporated by
reference in its entirety herein.
[0038] Referring to FIGS. 4 and 5, feedthrough 150 serves to
connect the electronic components or elements, surrounded by inner
wall 104, to electrode 120 located outside outer wall 102 of
housing 100. Feedthrough 150 typically comprises a feedthrough
ferrule 156, a conductive wire or pin 116, and a feedthrough
insulator 158. The feedthrough ferrule 156 is placed in a hole or
aperture in the housing 100 that is slightly larger than the outer
diameter of the main ferrule body. The ferrule 156 is then welded
to the housing 100. A conductive element 116 runs through a hole in
about the middle of the ferrule 156 such that an external end 136
(or T-shaped end) is coupled or connected to the electrode 120
while internal end 134 is connected to the electronics. The area
between the conductive wire 116 and the ferrule 156 is filled with
a hermetic insulator 158 such as glass and/or other suitable
material.
[0039] A securing assembly 302 supports and/or connects electrode
assembly 110 to housing 100. In one or more embodiments, securing
assembly 302 comprises an insulator cup 130 and a bracket 310 that
are configured to conform to the housing of IMD 10, 150 and 190,
respectively. For example, FIG. 7 shows that securing assembly 302
surrounds domed-shaped electrodes 160, which prevents electrodes
160 from inadvertently electrically shorting to the pill-shaped
hermetic housing 180. Domed-shaped securing assembly 302 also helps
push the electrodes 160 away from the housing 180 and into the
patient's 12 tissue.
[0040] Details of the insulator cup 130 and the bracket 310 are
depicted in FIGS. 11-14. Insulator cup 130 separates or insulates
electrode 120 from housing 100. Insulator cup 130 is configured to
surround an outer circumference of feedthrough 150 and extend to an
outer diameter. Insulator cup 130 can be circular, dome-shaped,
rectangular-shaped or another suitable shape in order to support a
surface electrode. In one embodiment, the insulator cup 130
includes at least one planar side 122a (also referred to as a first
side) possessing a flat or substantially flat surface for
connecting with housing 100. A second side 122b such as a nonplanar
side, of insulator cup 130 is exposed to body fluids.
[0041] In the embodiment depicted in FIG. 5, the insulator cup 130
preferably protrudes less than about 0.1 inches perpendicular from
the housing outer wall 102 to reduce any potential discomfort for
the patient. In another embodiment, the insulator cup 130 protrudes
less than about 0.175 inches from the housing outer wall 102. In
yet another embodiment, the insulator cup is flush with the
exterior of the housing 100. The electrode 120 is aligned with the
area of the housing 100 that is covered by the insulator cup 130.
In other embodiments, the electrode 120 is about aligned with the
area of the housing 100 that is covered by the insulator cup 130.
About aligned means that the angle is 45 degrees or less between
the plane that contains the perimeter of the outer electrode
surface 132 and the plane that contains the perimeter of the area
of the housing 100 that is covered by the insulator cup 130.
[0042] A variety of biostable insulative materials can be used to
form insulator cup 130. Exemplary materials that can be used to
manufacture insulator cups 130 can include polyetherimide (PEI),
polyaryletheretherketone (PEEK), acrylonitrile butadiene styrene
(ABS), and/or thermoplastic polyurethane (TPU); however, it should
be understood that other suitable polymers can also be used.
Insulator cups 130 can be manufactured by employing conventional
molding or machining techniques.
[0043] Bracket 310, shown in greater detail in FIGS. 11-14,
operates in conjunction with insulator cup 130 to form a securing
assembly 310. Bracket 310, configured to support and/or connect the
load of a surface electrode to the housing, can be Y-shaped,
substantially Y-shaped, X-shaped, or other suitable shapes. Each
leg 312a,b,c of bracket 310 can be integrally formed and spaced
apart from each other by an angle .theta.. Angle .theta. can range
from about 20 degrees to about 90 degrees. In another embodiment,
angle .theta. can range from about 20 degrees to about 180 degrees.
Typically, legs 312a,b,c are symmetrically spaced apart; however,
in other embodiments, legs 312a,b,c can be asymmetrically spaced
apart. In yet another embodiment, the bracket is disk shaped such
that it does not include legs. The disk bracket includes a hole for
the pin to pass therethrough. In yet another embodiment, the
bracket is integrally formed with the housing.
[0044] In one or more embodiments, retention bracket 310 can
include snap protrusions 410 that engage a retention lip 420 on the
insulator cup 130. The vertical extension 430 of the retention
bracket 310 is flexible such that pressing the insulator cup 130
onto the retention bracket 310 (causes the retention lip's lower
surface 440 to engage the snap protrusion's chamfer 446. The
interaction of the retention lip's lower surface 440 and the snap
protrusion's chamfer 446 causes the vertical extension 430 to flex
towards the retention bracket's center 424. Flexing towards the
retention bracket's center 424 allows the retention lip 420 to move
past the snap protrusion 410. Once the snap protrusions 410 are
located further from the housing outer wall 102 than the retention
lip 420, the snap protrusions 410 securely holds the insulator cup
130 in place because the snap protrusions 410 overhang or protrude
over the retention lip 420.
[0045] The interference between the snap protrusions 410 and the
retention lip 420 as the insulator cup 130 is pressed approximately
downward onto the bracket 310 forces at least one of the retention
bracket 310 and the insulator cup 130 to flex to allow the snap
protrusions 410 to move past the retention lip 420. As mentioned
above, the vertical extensions 430 can flex towards the bracket's
center 424, or in other words, can flex away from the retention lip
420. When the vertical extensions 430 flex towards the bracket's
center 424, the vertical extensions 430 flex approximately
horizontally. In another embodiment, flexing towards the bracket's
center 424 entails the vertical extension 430 rotating about its
intersection with the horizontal portion of the leg 312 that abuts
the outer wall 102 of the housing 100.
[0046] In another embodiment, the vertical extensions 430 do not
flex and the snap protrusion's chamfer 446 forces the retention lip
420 to curl upward or expand in diameter. In yet another
embodiment, the retention lip 420 has slots that allow the snap
protrusion 410 to move past the retention lip 420 without requiring
either the vertical extensions 430 or the retention lip 420 to
flex. In this embodiment, the insulator cup 130 is rotated after
the snap protrusions 410 have passed through the slots in the
retention lip 420 in order to lock the insulator cup 130 in
place.
[0047] FIG. 14 shows an embodiment where the retention bracket 310
is insert molded into the insulator cup 130. Overmolded extensions
450 of the retention bracket 310 are fully encased within the
insulator cup 130 to prevent the insulator cup 130 from moving
relative to the retention bracket 310. In particular, overmolded
extensions 450 of the retention bracket 310 assist insulator cup
130 to remain stationary relative to the retention bracket 310.
[0048] In one embodiment, the retention bracket 310 is manufactured
by stamping the general sheet metal shape and then bending the ends
of the sheet metal to form snap protrusions 410. In another
embodiment, the retention bracket 310 is machined from a metal
block using a multi-axis mill.
[0049] FIGS. 10A-E depict various stages of manufacturing a
low-profile electrode with a securing assembly 302. FIG. 10A
depicts a feedthrough that has been welded into a narrow hermetic
housing 300. FIG. 10B depicts a retention bracket 310 that has been
connected to the narrow hermetic housing 300. For example, the
retention bracket 310 can be welded to housing 100. FIG. 10C
depicts an insulator cup 130 that has been snapped onto the
retention bracket 310. FIG. 10D depicts an electrode 120 that has
been placed in on the insulator cup 130. The conductive wire 116
extends through a small hole 320 in the electrode 120. FIG. 10E
depicts a conductive wire 116 that was trimmed to be about flush
with the surface of the electrode 120 and then welded to the
electrode 120. Adhesive can be injected under the electrode 120 by
placing the tip of the adhesive applicator in the fill hole 144.
Excess adhesive is removed in a variety of ways. For example,
excess adhesive can be wiped away from the electrode 120.
[0050] In the embodiment show in FIGS. 11-13, the electrode 120
resides in an indentation 448 in the insulator cup 130. Indentation
448 can help prevent the electrode 120 from moving relative to the
insulator cup 130.
[0051] In other embodiments, the electrode 120 can be molded into
the insulator cup 130. For example, two weld anchor features can be
molded into the insulator cup 130 in addition to the electrode. The
two weld anchor features (e.g. one on each side of the electrode),
could be simultaneously stamped out with the electrode in a stamped
lead frame. The resulting subassembly can then be insert molded.
Thereafter, the stamping break-off tab could be removed to
electrically isolate the weld anchors from the electrode. This
process provides one insert molded part with an electrode in the
center of the insulator cup, and two weld anchors, one on each side
of the electrode. A hole in the electrode provides access for the
feedthrough wire to pass through the electrode for welding. The
weld anchors would be welded to the housing to keep the assembly
securely in place.
[0052] FIGS. 8-9 depict still yet another securing assembly 302 for
IMD 190. In this embodiment, an elongated, slender implantable
device 190 includes a rectangular hermetic housing 200. Low profile
rectangular electrode assemblies 204 can be located on the sides of
the long, slender implantable device 190. Rectangular insulator
cups 210 support rectangular electrodes 220. In this embodiment,
securing assembly includes insulator cup 130 adhesively coupled to
housing 100. Adhesive is injected into the fill holes 244 until
adhesive 140 begins to exit vents 246 to fill the area underneath
the electrode 120 that is between the insulator cup 130 and the
housing 100.
[0053] FIG. 4 depicts yet another embodiment in which electrode can
be further adhesively bonded to housing 100. Adhesive can be
injected into the fill hole 144 until adhesive 140 begins to exit
the vent 146 from filling the area underneath the electrode 120
that is between the insulator cup 130 and the housing 100.
Exemplary adhesive 140 can include silicone-based medical adhesive,
epoxy resin or other suitable material.
[0054] Although the present disclosure has been described in
considerable detail with reference to certain disclosed
embodiments, the disclosed embodiments are presented for purposes
of illustration and not limitation and other embodiments of the
disclosure are possible. For example, other embodiments can include
ceramic brazed feedthroughs can also be used without departing from
the spirit of this disclosure.
* * * * *